If you’ve a taste for scholarly review papers (and who doesn’t?!) and an interest in fear and learning (ditto), a rigorous but substantial treat awaits you, free, in the January issue of Nature Neuropsychopharmacology. Gregory Quirk, a former post-doc in the lab of fear-research pioneer Joe LeDoux (whom I once profiled in Scientific American Mind, is lead author on a review of what we know about how fear learning is extinguished (a poor term; fears are not so much extinguished as replaced by stronger lessons about not fearing) and then revived. He and co-author Kevin Meuller also discuss the potential for drugs for fear and anxiety disorders (OCD, PTSD, etc.) that seem to involve dysfunctions in fear extinction.

Goods stuff for the heart. Here’s the abstract:

Emotional learning is necessary for individuals to survive and prosper. Once acquired, however, emotional associations are not always expressed. Indeed, the regulation of emotional expression under varying environmental conditions is essential for mental health. The simplest form of emotional regulation is extinction, in which conditioned responding to a stimulus decreases when the reinforcer is omitted. Two decades of research on the neural mechanisms of fear conditioning have laid the groundwork for understanding extinction. In this review, we summarize recent work on the neural mechanisms of extinction learning. Like other forms of learning, extinction occurs in three phases: acquisition, consolidation, and retrieval, each of which depends on specific structures (amygdala, prefrontal cortex, hippocampus) and molecular mechanisms (receptors and signaling pathways). Pharmacological methods to facilitate consolidation and retrieval of extinction, for both aversive and appetitive conditioning, are setting the stage for novel treatments for anxiety disorders and addictions.